This invention relates to vehicle drive systems, and more particularly to low-emission vehicles using converters for converting fuel to mechanical or electrical energy.
Vehicular fuel consumption has been very important at least since the early 1970s. The Government has mandated fleet fuel economy standards, and has also mandated vehicular emission standards. In order to accommodate these standards, internal combustion engines have become smaller and more efficient, vehicles have been made lighter, and various improvements have been made to the emission control.
In some regions, local conditions cause vehicular emissions to be concentrated, which has led to more stringent fuel economy and emission control standards. Industry response to these more stringent standards has been to investigate and experiment with electric vehicles. However, the state of technology is not adequate to provide electric automobiles with viable range and cost.
Another avenue of investigation and experimentation includes hybrid electric vehicles, which include both electric motors and sources of electrical power, such as fuel cells and internal-combustion/electric generation. Experimental vehicles are in use in various locations, in which diesel engines coupled to alternators are used to charge a traction battery, and the electrical energy is used to power the vehicle. Such arrangements are described, for example, in U.S. Pat. No. 5,828,201, issued Oct. 27, 1998 in the name of Hoffman, Jr. et al.; U.S. Pat. No. 5,869,950, issued Feb. 9, 1999 in the name of Hoffman, Jr. et al.; U.S. Pat. No. 5,910,722 issued Jun. 8, 1999 in the name of Lyons et al.; U.S. Pat. No. 5,949,210 issued Sep. 7, 1999 in the name of Gataric et al; allowed application Ser. No. 09/192,645, filed Nov. 16, 1998 in the name of Jones et al.; allowed application Ser. No. 09/044,670, filed Mar. 20, 1998 in the name of Lyons et al.; U.S. Pat. No. 5,941,328 issued Aug. 24, 1999 in the name of Lyons et al.; U.S. Pat. No. 5,929,595 issued Jul. 27, 1999 in the name of Lyons et al.; U.S. Pat. No. 5,950,752 issued Sep. 14, 1999 in the name of Lyons; U.S. Pat. No. 6,091,228, issued Jul. 18, 2000 in the name of Chady et al.; application Ser. No. 09/080,148, filed May 18, 1998 in the name of Lyons et al; and U.S. Pat. No. 6,072,287 issued Jun. 6, 2000 in the name of Gataric, and entitled xe2x80x9cPolyphase AC Machine Controllerxe2x80x9d.
Improved emission control arrangements are desired.
A vehicle according to an aspect of the invention includes a fuel-to-electric converter for converting the energy in fuel into electric energy. The fuel-to-electric converter generates an exhaust fluid during operation. An electric machine is coupled to a drive arrangement of the vehicle, for propelling the vehicle when energized by the electric energy, and for generating electrical energy during deceleration. An exhaust cleaning arrangement is coupled to the fuel-to-electric converter, for cleaning the exhaust fluid. The exhaust cleaning arrangement provides improved performance when heated. A control arrangement is coupled to the electric machine and to the exhaust cleaning arrangement, for coupling the electrical energy from the machine to the exhaust cleaning arrangement during the deceleration, for heating the exhaust cleaning arrangement. In a preferred embodiment of the invention, the fuel-to-electric converter includes an internal combustion engine including a driven shaft, and an electrical generator coupled to the shaft. The electrical generator is preferably a multiphase alternator. In a preferred embodiment of the invention, the exhaust cleaning apparatus comprises a catalytic converter. One embodiment of the invention further includes electrical heaters thermally coupled to the exhaust cleaning arrangement and electrically coupled for receiving the electrical energy from the machine, and for heating the exhaust cleaning arrangement. A vehicle according to another aspect of the invention has the exhaust cleaning arrangement coupled to the fuel-to-electric converter by a path for the flow of the fluid exhaust, and has the electrical heaters physically attached to the path for the flow of the fluid exhaust.
A method for operating a vehicle according to an aspect of the invention includes the step of converting the energy contained in fuel into electrical energy by use of a machine which generates a fluid exhaust. The electrical energy is converted into motion of a vehicle during acceleration. During deceleration of the vehicle, energy of motion is converted into deceleration electrical energy. Exhaust is cleaned by means of a temperature-dependent apparatus. Deceleration electrical energy is applied to the apparatus for heating the apparatus.